This postcard looks like it should be a linen card, but it has a smooth finish to it, so I won't put it in that category. However, everything else about the card makes it look as if it's from that time period. It was never used, and was published by the Sanborn Souvenir Co. of Denver, like the Estes Park Chalets Linen Postcard was.
On the back of the card a little information is included about its subject:
"The great open air amphitheater at the Park of the Red Rocks was opened in 1941. This great bowl seating 12,000 or more people is flanked on each side with huge red sandstone cliffs and the stage is at the foot of another great block of stone. These great rocks from natural sounding boards offering splendid acoustics as well as a marvelous setting."
Visit the Jefferson County, CO GenWeb Project!
Visit the Red Rocks Park & Amphitheater